36 ART. 15— TAMEMASA HAGA. 



lead peroxide, which gives it again the bluish-violet colour of peroxyl- 

 aminesulphonate. By removing sulphate and hydroxylaminedi- 

 sulphonate from the solution by barium hydroxide, nearly all the 

 hydroxylaminetrisulphonate can be crystallised out; the mother liquor 

 containing the nitrite may then be tested in any of the usual ways 

 for this salt. 



It was important to know whether any nitrate is formed by the 

 decomposition, and therefore necessary first to get rid of all the 

 nitrite present by a process that does not convert any of it into 

 nitrate. The nitrite was accordingly changed into aminetrisulphonate 

 (nitrilosulphate) by adding enough potassium carbonate and then 

 passing in sulphur dioxide until the solution became acid, at which point 

 the aminetrisulphonate that had been produced at once hydrolysed 

 (this Journal 6, 65). Lastly, by blowing in air until all the remaining 

 sulphur dioxide had been expelled, the acid solution was left free 

 from either nitrite or sulphite, and, therefore, ready for testing for 

 nitrate. None of this salt was found. The application of the process 

 of sulphonating the nitrite to the determination of total nitrogen in 

 solution, is described on page 39). 



The testing for aminemonosulphonate (aminosulphate) among 

 the products of decomposition of a peroxylaminesulphonate is not an 

 easy matter. The method adopted was to oxidise nil the hydroxyl- 

 aminedisulphonate by boiling the solution wifh lead peroxide until it 

 was again colourless. The nitrite was then oxidised by pouring the 

 solution into potassium permanganate solution to which sulphuric 

 acid had been added. Mercuric nitrate solution then precipitated 

 from it a little oxymercuric aminemonosulphonate (this Journal, 9, 

 242), which, when treated with hydrogen sulphide, left the acid again 

 in solution. By evaporation and addition of strong sulphuric acid, 







